Bleaching composition

ABSTRACT

Bleaching compositions having mixtures of persulfate bleaching compounds and organic peroxy-compounds in proportions such that the weight ratio of available oxygen from the persulfate to that from the organic peroxy compounds is up to 3:1. The compositions are particularly useful for washing and bleaching at lower temperatures. The bleaching compositions can be employed with detergent compounds to provide bleaching and detergent compositions having from 0.1 to 3 percent available oxygen by weight. A method aspect of the invention comprises treating fibrous materials in aqueous solution with the mixture of bleaching agents of the invention at a concentration of from 1 to 100 parts per million by weight of available oxygen.

252-95. AU 165 EX 0 United States Patent [1 1 [111 3,773,673 Jenkins etal. 1 Nov. 20, 1973 [54] BLEACHING COMPOSITION 3,075,921 l/1963Brocklehurst et a1. 252/99 [75] Inventors: Peter Anthony Jenkins,Corbridge;

Alexander Ritchie, Newcastle upon Examm"Mayel' wembkm Tyne, both fEngland Attorney-Richard C. Witte et al.

[73] Assignee; The Procter & Gamble Company,

Cincinnati, Ohio ABSTRACT [22] Filed; No 20, 1972 Bleaching compositionshaving mixtures of persulfate bleaching compounds and organicperoxy-compounds [21] Appl. No.: 308,075

Related US. Application Data [63] Continuation of Ser. No. 96,650, Dec.9, 1970,

abandoned.

[52] US. Cl 252/95, 252/99, 8/111 [51] Int. Cl. Clld 7/54 [58] Field ofSearch 252/95, 99, 8/111 [56] References Cited UNlTED STATES PATENTS3,558,497 1/1971 Lawes 252/99 3,384,596 5/1968 Moyer 252/99 X inproportions such that the weight ratio of available oxygen from thepersulfate to that from the organic peroxy compounds is up to 3:1. Thecompositions are particularly useful for washing and bleaching at lowertemperatures. The bleaching compositions can be employed with detergentcompounds to provide bleaching and detergent compositions having from0.1 to 3 percent available oxygen by weight. A method aspect of theinvention comprises treating fibrous materials in aqueous solution withthe mixture of bleaching agents of the invention at a concentration offrom 1 to 100 parts per million by weight of available oxygen.

14 Claims, No Drawings BLEACHING COMPOSITION This application is acontinuation of US. Application 96,650, filed December 9, 1970 nowabandoned.

The invention relates to a bleaching composition comprising asynergistic mixture of oxygen bleaching agents. More particularly, thisinvention is based on the surprising discovery that a particular mixtureof oxygen bleaching agents is more effective at a given level ofavailable oxygen than either of its components alone.

Among the most commonly used inorganic oxygen bleaching agents aresodium perborate, percarbonate and the like. These compounds have littlebleaching activity at temperatures below about 85C. Other known types ofinorganic bleaching agents, which are more effective at temperaturesbelow 85C, include persulfuric acid (sometimes known as Caro's Acid) andits salts and acid salts, and mixed salts, such as Oxone (trade name)which consists essentially of the compound KHSO K,SO 2KHSO Among organicperoxycompounds known to have bleaching properties are the aliphatic andaromatic percarboxylic acids based on the radical It has nowsurprisingly been found that certain mixtures of persulfates and organicperoxy-compounds have more bleaching effect than members of either classalone when used at the same concentration of available oxygen.

The available oxygen" is that which is free to react with oxidizablesubstances, for instance one atom for each molar equivalent of an SO orCO H radical. The amount is usually expressed as a proportion by weightof a relevant compound, mixture or composition.

According to the invention there is provided a bleaching compositionwhich comprises a mixture of a persulfate and an organic peroxy-compoundin proportions such that the weight ratio of available oxygen derivedfrom the persulfate to that derived from the organic peroxy-compound isup to 3:l.

The invention also provides detergent compositions containing such amixture of bleaching agents and a detergent substance.

The invention also provides a method of bleaching fibrous materials bytreating them in an aqueous solution containing from 1 to 100 parts permillion by weight of available oxygen derived from such a mixture ofbleaching agents.

Preferred inorganic persulfates are alkali metal or ammoniumpersulfates, such as sodium or potassium monopersulfate, andparticularly the mixed salt KHSO K 50 2KHSO or the corresponding sodiumsalt.

Organic peroxy-compounds are preferably the aliphatic or aromaticpercarboxylic acids and their alkali metal and ammonium salts. Among thealiphatic peracids may be named peracetic acid, perpropionic acid, up toperlauric acid and the like. The preferred peracids are aromaticperacids such as perbenzoic acid and nuclearsubstituted perbenzoicacids, especially those having a melting point above 50C, such as thosedescribed in British Patent Specification 886,188. Especially preferredis p-methoxyperbenzoic acid.

The mixed bleaching agent should preferably be present in the bleachingsolution at a concentration such as to provide from 1 to 100 parts permillion (ppm) by weight of available oxygen in the solution. Below about1 ppm little bleaching effect is observed; above about ppm there may beno advantage for the mixture over the peracid alone. A preferred rangeof available oxygen content is from 10 to 70 ppm.

Addition of quite small proportions of persalt to the organicperoxy-compounds provides mixtures performing better (at constantavailable oxygen level) than the peroxy-compound alone, but it ispreferred to employ mixtures wherein the weight ratio of availableoxygen derived from the persulfate to that derived from the peroxycompound is at least 1:10. At the other extreme there is little or noadvantage for the mixture over the peracid alone when the ratio isgreater than 3:1, and preferably it is not greater than 1:]. The optimumratio, defined as that which provides the maximum bleachingeffectiveness per unit of available oxygen, is generally approximately1:2. As will be understood, the economic optimum ratio may be somewhatdifferent depending upon the relative cost of the two bleachingcomponents.

The bleaching mixtures are preferably used at pH (of the bleachingliquor) in the range from 8.5 to 1 L5, especially from 9.5 to 10.5. Theyare effective at moderate washing temperatures, below about C, and areparticularly valuable for washing and bleaching at temperatures notexceeding 60C, for instance within the range from 40 to 55C. Though theyare effective at temperatures of about 85C up to the boil, other andwell-known bleaching agents, such as the perhydrates, are also effectiveat these temperatures, so that the compositions of the invention findtheir greatest utility when used for washing and bleaching at lowertemperatures.

The bleaching agents of the invention can be used in the presence ofcompatible water-soluble organic detergents to provide a detergentcomposition, which can contain other ingredients such as inorganicbuilder salts and/or organic sequestrant builder salts. Particularlysuitable organic detergents are the anionic detergents such as soap,alkylaryl sulfonates, alkyl sulfates, alkane sulfonates, olefinsulfonates, fatty acid isethionates and fatty acyl taurides. Nonioniczwitterionic and cationic detergentswhich are substantially unaffectedin solution by the bleaching agents can also be used. Suitable inorganicsalts and builder salts include those commonly used in detergentcompositions such as alkali metal ortho-, .pyroand tripolyphosphates,and more condensed phosphates, and alkali metal carbonates,bicarbonates, silicates, sulfates and borates. Organic alkaline buildersalts such as nitrilotriacetates, ethylenediamine tetraacetates,ethane-l-hydroxy-l, ldiphosphonates and the like can also be used. Thesodium or potassium, especially the sodium salts, are most commonlyemployed. The bleaching agents can either be used in solution togetherwith a suitable combination of these substances or they can constitutepart of a detergent composition containing at least some of thesecomponents. Preferably such detergent compositions are particulate,either flowable powders or aggregates or briquettes.

In cases where the moisture or some other components of the detergentcomposition might interact undesirably with the solid bleaching agents,it is desirable to take precautions to minimize contact between thebleaching agents and between them and other components of the detergentcomposition. This can be achieved by pelletizing or granulating thebleaching agents individually, together, or in admixture with an inertsubstance or one which has a stabilizing effect, such as certaininorganic salts. This considerably reduces the area of contact betweenthe bleaching agents and the other components. Alternatively, thebleaching agents, individually or together, or in admixture with inertor stabilizing substances, can be coated with an inert protectivematerial which is removed by solution, melting or abrasion in thewashing process.

The detergent compositions or the aqueous bleaching solutions, cancontain other compatible minor ingredients commonly employed in suchcompositions, such as soil-suspending agents, for example carboxymethylcellulose; copolymers of methyl vinylether and maleic anhydride andother water-soluble polymeric substances; suds-controlling agents, suchas fatty acid ethanolamides to improve suds stability; or nonionicdetergents, high molecular weight (C and over) saturated fatty acids ortheir soaps, and the like to depress sudsing; optical brighteners;tarnish inhibitors; proteolytic, amylolytic or lipolytic enzymes; dyes;perfume; and the like.

It is of course preferred to incorporate the bleaching agents indetergent compositions in proportions such that when the detergentcomposition is used at the usual and proper concentration forsatisfactory washing performance, the concentration of available oxygenin the washing solution is in the ranges described hereinbefore. Thus,in conventional type heavy duty household detergents an available oxygencontent in the range about 0.1 to 3 percent by weight of the compositionis often suitable, especially about 0.25 to 1 percent.

The invention is illustrated by the following Examples.

EXAMPLE I A solution was prepared containing 4 g. per liter of adetergent composition consisting of, by weight;

Linear alkyl benzene sulfonate (alkyl chain C Sodium toluene sulfonate1.8%

Sodium tripolyphosphate 46.2%

Sodium silicate 7.3%

Coconut monoethanolamide 1.8%

Sodium carboxymethylcellulose 1.0%

Sodium sulfate 12.4%

Miscellaneous minor components 1.9%

Moisture 10.0% The solution was warmed to 49C. A mixture of potassiummonopersulfate in the form of Oxone" (trade name) and ofp-methoxyperbenzoic acid in proportions such as to provide 22.2 partsper million available oxygen from Oxone" and 44.5 parts per million frompmethoxy perbenzoic acid were added to the solution, and the pH adjustedto 10.0 by addition of dilute alkali. Tea-stained cloth swatches weretreated at 49C for minutes in this solution, rinsed and dried.Comparison of the reflectance of the untreated and treated clothsindicated 77.1 percent stain-removal.

Comparative tests using Oxone" alone, and pmethoxyperbenzoic acid alone,each at a concentration such as to provide 66.7 parts per million ofavailable oxygen in the solution gave 53.5 and 72.5 percentstain-removal, respectively.

EXAMPLE ll ln a test similar to that of Example 1 using the samebleaching agents in proportions such that Oxone" provided 5 parts permillion available oxygen and pmethoxy perbenzoic acid provided 15 partsper million, stain-removal values were,

Mixture 58.5%

P-methoxy perbenzoic acid alone at 20 ppm available oxygen 52.3% Oxonealone at 20 ppm available oxygen 38.3%

EXAMPLE III A bleaching test was carried out in similar conditions tothose of Example 1, but reating the stained test cloths in a solutiononly containing Oxone and perbenzoic acid (adjusted to pH 9.5) at levelssuch that each provided 17.5 parts per million of available oxygen. Theresults were compared with those given by each agent alone at aconcentration providing 35 ppm available oxygen. Stain removal figureswere:

Mixture 53% Perbenzoic acid 45% Oxone 28% What is claimed is:

l. A bleaching composition which consists essentially of a mixture of analkali metal or ammonium monopersulfate and an organic peroxy-compound,in proportions such that the weight ratio of available oxygen derivedfrom the monopersulfate to that derived from the peroxy compound is from1:1 to 1:3; said organic peroxy-compound being selected from the groupconsisting of perbenzoic acid, p-methoxy perbenzoic acid and the alkalimetal and ammonium salts thereof.

2. The bleaching composition of claim 1 wherein the monopersulfate is analkali metal monopersulfate.

3. The bleaching composition of claim 1 wherein the monopersulfateconsists essentially of a mixed salt of formula MHSO M 50 and 2MHSOwherein M is potassium or sodium.

4. The bleaching composition of claim 1 wherein the organic peroxycompound is perbenzoic acid or an alkali metal or ammonium salt thereof.

5. The bleaching composition of claim 1 wherein the organic peroxycompound is p-methoxy perbenzoic acid.

6. A bleaching and detergent composition consisting essentially of awater-soluble organic detergent; and the mixture of monopersulfate andorganic peroxycompound bleaching compounds of claim 1; the weight ratioof available oxygen derived from the monopersulfate to that derived fromthe peroxy compound being up to 321; the bleaching and detergentcomposition having from 0.1 to 3 percent available oxygen by weight.

7. The bleaching and detergent composition of claim 6 wherein there isalso present an inorganic builder salt or organic sequestrant buildersalt or mixtures thereof.

8. The bleaching and detergent composition of claim 7 wherein theavailable oxygen by weight of the composition ranges from 0.1 to 3percent.

9. The bleaching and detergent composition of claim 8 wherein theavailable oxygen by weight of the composition ranges from 0.25 to 1percent.

6 12. The method of claim 1] wherein the pH value is from 9.5 to 10.5.

13. The method of claim 10 wherein the solution is at a temperature notexceeding C.

14. The method of claim 13 wherein the solution is at a temperaturewithin the range from 40C to 55C. l 1! i i

2. The bleaching composition of claim 1 wherein the monopersulfate is analkali metal monopersulfate.
 3. The bleaching composition of claim 1wherein the monopersulfate consists essentially of a mixed salt offormula MHSO4, M2SO4 and 2MHSO5 wherein M is potassium or sodium.
 4. Thebleaching composition of claim 1 wherein the organic peroxy compound isperbenzoic acid or an alkali metal or ammonium salt thereof.
 5. Thebleaching composition of claim 1 wherein the organic peroxy compound isp-methoxy perbenzoic acid.
 6. A bleaching and detergent compositionconsisting essentially of a water-soluble organic detergent; and themixture of monopersulfate and organic peroxy-compound bleachingcompounds of claim 1; the weight ratio of available oxygen derived fromthe monopersulfate to that derived from the peroxy compound being up to3:1; the bleaching and detergent composition having from 0.1 to 3percent available oxygen by weight.
 7. The bleaching and detergentcomposition of claim 6 wherein there is also present an inorganicbuilder salt or organic sequestrant builder salt or mixtures thereof. 8.The bleaching and detergent composition of claim 7 wherein the availableoxygen by weight of the composition ranges from 0.1 to 3 percent.
 9. Thebleaching and detergent composition of claim 8 wherein the availableoxygen by weight of the composition ranges from 0.25 to 1 percent.
 10. Amethod of bleaching fibrous materials which comprises treating them inan aqueous solution of the composition of claim 1, the concentration ofsaid composition being such that there is present in the aqueoussolution from 10 to 70 parts per million by weight of available oxygen.11. The method of claim 10 wherein the bleaching solution has a pH offrom 8.5 to 11.5.
 12. The method of claim 11 wherein the pH value isfrom 9.5 to 10.5.
 13. The method of claim 10 wherein the solution is ata temperature not exceeding 60*C.
 14. The method of claim 13 wherein thesolution is at a temperature within the range from 40*C to 55*C.